A research collaboration led by Tohoku University has unveiled a copper-based shape memory alloy that retains functionality at cryogenic temperatures down to -200C. This breakthrough material offers a viable actuator solution for space technologies and hydrogen systems where extreme cold conditions are common.
Conventional shape memory alloys (SMAs) made of nickel-titanium lose their shape recovery abilities below -20C. Other alloys that function in colder environments lack the mechanical strength for practical use. The newly developed Cu-Al-Mn alloy addresses this gap, offering substantial mechanical output at sub -100C temperatures.
The research team-which includes Iwate University, JAXA, NAOJ, Tokyo City University, and Kyoto University-successfully demonstrated a prototype heat switch actuator made from the alloy. This device toggles between thermal contact states in response to temperature shifts and was shown to operate efficiently at -170C. Researchers confirmed that the transition temperature can be tuned by adjusting alloy composition.
"We were very happy when we saw that it worked at -170C," said Toshihiro Omori from Tohoku University. "Other shape memory alloys simply can't do this."
The Cu-Al-Mn alloy is the first to combine high actuation strength with cryogenic performance, opening the door to compact, efficient mechanical components in space-based cooling systems, such as those used in telescopes. These actuators also hold promise for hydrogen transport and storage technologies that support carbon-neutral energy systems.
Research Report:Shape memory alloys for cryogenic actuators
